Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 10 of 10 for “"configurational stability"”.
-
Stereochemistry of small molecules: Configurational and conformational control
… in synthesis is associated with the configurational stability of the metal-bearing stereogenic center. We were interested in the configurational stability of lithiated and magnesiated nitriles. We developed a new series of lithio-cyclopropylnitriles bearing chelating groups for …
-
Synthetic and Mechanistic Studies of Carbamate-Directed Lithiation Reactions: (1) Assymetric Deprotonation of N-Boc Indolines. (2) the Relationship Between Reactivity and Directing Group Orientation
… $\alpha$-lithio carbamates have increased configurational stability relative to more flexible analogs. An increase in the rate of epimerization of $\alpha$-lithio carbamates in the presence of $N,\ N,\ N\sp\prime ,\ N\sp\prime$-tetramethylethy lenediamine suggests that the rate-determining …
-
Study of Synthesis, Reactions and Enantiomerization of C<sub>α</sub>-Chiral Grignard Reagents
… associated with their synthesis, and their low configurational stability. We have studied these problems in three different modules of this project. Reactions of 1-magnesio-2,2-diphenyl-cyclopropylcarbonitrile with carbon electrophiles are first attempted in order to expand the utility of this …
-
Studies on stereospecific diketopiperazine oxidation and applications to the synthesis of complex epidithiodiketopiperazines
… as well as the stereochemical outcome and the configurational stability of the product diols. An example of a subsequent thiolation was then demonstrated to proceed under retention of stereochemistry, in contrast to the stereoinvertive thiolations previously observed in several total syntheses. …
-
Synthesis of new chiral pyrylium salts, the corresponding phosphinine and pyridine derivatives and the kinetic studies of the epimerization of pyrylium salts.
… chiral pyrylium salts led us to investigate the configurational stability of chiral centers alpha to the pyrylium ring. Although no epimerizable (or even racemizable) pyrylium salts have been reported, deuterium exchange at ortho and especially para benzylic positions is well-known, suggesting …
-
Part I. Cytochrome c oxidase active-site modeling: Synthesis and characterization of new unsymmetrical tris(imidazole- and pyridine-appended) picket-fence porphyrins and their metal complexes. Part II. Toward fullerene-based radiopharmaceuticals: High-yield neutron activation of endohedral holmium-165 metallofullerenes
… been specifically designed to confer long-term configurational stability and allow synthetic manipulations to be easily performed without fear of atropisomer interconversions. The compounds also incorporate a covalently-linked, axially-offset tris(heterocycle) coordination site for a copper ion, …
-
Synthesis of Biologically Active Tropolones and Stereochemically Rich Compounds via Cross-Coupling Reactions
… characteristics, potential ring-puckering, and configurational stability have enabled the synthesis of atropisomeric troponoid-benzenoid structures. Our ability to synthesize atropisomeric troponoid-benzenoid compounds, through cross-coupling reactions, paves the way for entry into a whole new …
-
Studies on the Synthesis, Function, and Properties of Troponoids
… tendency of the tropolone scaffold to enhance configurational stability among its substituents with few exceptions.</p> <p>The third chapter discusses our discovery and analysis of the magnesium activated aqueous fluorescence of tropolone derivatives. Through a newly developed, late-stage …
-
Efficient & Novel Approaches to Relay Chirality in the Synthesis of Planar Chiral Metallocenes
… conformational isomer which allowed the configurational stability of the chiral metal center to be measured which suggested that a mechanism did exist for epimerisation at metal but occurred only at an ambient temperature over several hours. Chiral metallocyclopentadiene complexes were …
-
Development of first principles paramagnetic NMR methodologies to probe the complex local structural properties of Li-ion battery materials
… material, a methodical investigation of the configurational stability from first principles gives insight into the preferred site configurations. The combination of experimental $^7$Li NMR spectra and hyperfine shift DFT calculations of the so-found stable Li environments allows to unravel …